Gene structure,transcripts and calciotropic effects of the PTH family of peptides in <Emphasis Type=Italic>Xenopus</Emphasis> and chicken

Background  

Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evolution of these proteins. Although PTH and PTHrP have been intensively studied in mammals their function in other vertebrates is poorly documented. Amphibians and birds occupy unique phylogenetic positions, the former at the transition of aquatic to terrestrial life and the latter at the transition to homeothermy. Moreover, both organisms have characteristics indicative of a complex system in calcium regulation. This study investigated PTH family evolution in vertebrates with special emphasis on Xenopus and chicken.     

Effect of airflow rate on yields of Steinernema carpocapse Az 20 in liquid culture in an external-loop airlift bioreactor

Maximization of the contact between males and females is a key factor in the production of the nematode Steinernema carpocapsae in a bioreactor.%The influence of the airflow rate in male and female distribution and mass production in an external-loop bioreactor with a deceleration zone was studied. When operating at an airflow rate of 0.05 vvm, a high retention of females in the deceleration zone of the bioreactor was observed and a larger nematode productivity was obtained. At this aeration rate there was a higher proportion of males in that zone, which together with the lower circulation rate, increases the probability of encounters, thereby explaining the increase in productivity.     

The effect of chloroquine on the production of interferon-gamma, interleukin (IL)-4, IL-6, and IL-10 in Plasmodium chabaudi chabaudi in infected C57BL6 mice

The effect of chloroquine (CQ) on the production pattern of interferon (IFN)-gamma, interleukin (IL)-4, IL-6, and IL-10 in female C57BL6 mice infected with Plasmodium chabaudi chabaudi AS was evaluated during a period of 35 days. Our data confirm that there is a switch from a T helper cell (Th)1 to a Th2 response during malaria infection in this model. Proliferation assays showed a decreased stimulation index in infected mice that was further reduced in infected mice treated with CQ. Noninfected control mice treated with CQ showed an increase production of IFN-gamma. However, no detectable changes in IL-4, IL-6, and IL-10 production were observed in this group. CQ treatment of infected mice resulted in parasite clearance that was associated with an earlier production of IL-4, IL-6, and IL-10 when compared with nontreated infected mice. We suggest that this earlier switch to a Th2 response is a consequence of parasite killing rather than CQ interference with cytokine production.     

Overview of malaria control in the Americas

The malaria endemic countries of the Americas have adopted in 1992 the WHO Global Malaria Control Strategy whose difficulties of implementation have been compounded to a major reform in the health sector, as the countries adjust to conform to financial scarcity and new economic policies. Most countries of the Region have reoriented its control program from eradication of malaria to the elimination of malaria mortality and morbidity. The Region has advanced towards these objectives having already reduced its mortality by 60% and is now in the final stages of applying new tools to control transmission and rapidly advance to reduce the incidence of malaria in the Americas.     

Structural composition and differential anticoagulant activities of dermatan sulfates from the skin of four species of rays, Dasyatis americana, Dasyatis gutatta, Aetobatus narinari and Potamotrygon motoro

We compared the disaccharide composition of dermatan sulfate (DS) purified from the ventral skin of three species of rays from the Brazilian seacoast, Dasyatis americana, Dasyatis gutatta, Aetobatus narinari and of Potamotrygon motoro, a fresh water species that habits the Amazon River. DS obtained from the four species were composed of non-sulfated, mono-sulfated disaccharides bearing esterified sulfate groups at positions C-4 or C-6 of N-acetyl galactosamine (GalNAc), and disulfated disaccharides bearing esterified sulfate groups at positions C-2 of the uronic acid and at position C-4 or C-6 of GalNAc. However, DS from the skin of P. motoro presented a very low content of the disulfated disaccharides. The anticoagulant actions of ray skin DS, measured by both APTT clotting and HCII-mediated inhibition of thrombin assays, were compared to that of mammalian DS. DS from D. americana had both high APTT and HCII activities, whereas DS from D. gutatta showed activity profiles similar to those of mammalian DS. In contrast, DS from both A. narinari and P. motoro had no measurable activity in the APTT assay. Thus, the anticoagulant activity of ray skin DS is not merely a consequence of their charge density. We speculate that the differences among the anticoagulant activities of these three DS may be related to both different composition and arrangements of the disulfated disaccharide units within their polysaccharide chains.     

Acidophilic granulocytes of the marine fish gilthead seabream (<Emphasis Type="Italic">Sparus aurata</Emphasis> L.) produce interleukin-1β following infection with<Emphasis Type="Italic"> Vibrio anguillarum</Emphasis>

The fish immune response to Gram-negative bacteria is poorly understood. In this study, we use a monoclonal antibody (mAb) specific to acidophilic granulocytes from the marine fish gilthead seabream (Sparus aurata L.), together with an antiserum specific to interleukin-1 (IL-1) from this species, in order to investigate whether these cells are involved in the immune response against the pathogenic bacterium Vibrio anguillarum and, in particular, in the production of the pro-inflammatory cytokine IL-1. We found that gilthead seabream head-kidney, peritoneal exudate and peripheral blood leukocytes accumulated proIL-1 intracellularly when challenged in vitro with V. anguillarum, whereas only peritoneal exudate and blood leukocytes were able to accumulate proIL-1 following infection. Importantly, the blood leukocytes from infected animals that accumulated proIL-1 were shown to be the acidophilic granulocytes. A rapid mobilization of such cells from the head-kidney to the site of inflammation following infection with V. anguillarum was also observed. This work was supported by the Spanish Ministry of Science and Technology (grants BIO2001-2324-C02-02 and AGL2002-03529, and fellowship to J. García-Castillo), Spanish Ministry of Education, Culture and Sport (fellowship to E. Chaves-Pozo) and Fundación Séneca, Coordination Centre for Research (grant PI-51/00782/FS/01 and fellowship to P. Pelegrín).E. Chaves-Pozo and P. Pelegrín contributed equally to this work.     

FTIR spectroelectrochemical study of the activation and inactivation processes of [NiFe] hydrogenases: effects of solvent isotope replacement and site-directed mutagenesis

The kinetics of the activation and anaerobic inactivation processes of Desulfovibrio gigas hydrogenase have been measured in D₂O by FTIR spectroelectrochemistry. A primary kinetic solvent isotope effect was observed for the inactivation process but not for the activation step. The kinetics of these processes have been also measured after replacement of a glutamic residue placed near the active site of an analogous [NiFe] hydrogenase from Desulfovibrio fructosovorans. Its replacement by a glutamine affected greatly the kinetics of the inactivation process but only slightly the activation process. The interpretation of the experimental results is that the rate-limiting step for anaerobic inactivation is the formation from water of a -OH^– bridge at the hydrogenase active site, and that Glu25 has a role in this step.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00775-004-0559-7